Ground covering elements of artificial stone material

ABSTRACT

The invention relates to an artificial stone floor element with a basic shape that corresponds to the combination of a plurality of square basic elements, especially to an angular floor element. The floor element includes projections and recesses along its peripheral sides of the basic element when seen from the centre of the respective top face of the basic element is substantially point-symmetric with respect to its mid-point. The floor element in further embodiments includes a profile that consists of three projections and three recesses.

This application is a Divisional of U.S. patent application Ser. No.10/633,663 filed on Aug. 5, 2003, which is a continuation of PCTApplication Number PCT/EP01/11151 filed on Sep. 26, 2001, which claimspriority from German application number 101 05 055.0 filed on Feb. 5,2001; which are all incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates, according to a first aspect, to a ground coveringelement of artificial stone material, having a basic shape correspondingto a unification of several square basic elements, in particular anangular ground covering element, the ground covering element comprisingprojections and recesses all around its circumference, allcircumferential basic element sides—as seen from the center of therespective basic element upper side—having substantially the sameprofile which is substantially point-symmetric with respect its halvingpoint.

2. Description of the Prior Art

Basic elements of this kind, also angular ground covering elements, areknown. So far, the design of the profile has been based more or less onintuition.

It is an object of the invention to purposefully design the profile inorder to obtain a good compromise between inter-engagement effect incase of not completely perfect mutual orientation of adjacent groundcovering elements and strength of the inter-engagement between adjacentground covering elements.

SUMMARY OF THE INVENTION

To meet this object, the aforementioned ground covering element ischaracterized in that this profile consists of three projections andthree recesses. It will be elucidated in more detail further below thatthis number will result in an optimum compromise in the sense of theunderlying object mentioned.

The afore-mentioned “artificial stone material” in most cases isconcrete. As a further preferred possibility, brick-like materialsshould be mentioned. In general, there are also all materialsconceivable having embedded therein additives or fillers in binders(e.g. also plastics) hardening as a function of time, in particularpolymer concrete. The word “substantially” was used with consideration,since in most cases, the profile is not equal on all circumferentialbasic element sides in the strict sense and since the point symmetry isnot realized in the strict sense in most cases. Ground covering elementsof artificial stone material are manufactured with such largemanufacturing tolerances that this is of itself sufficient to preventthe manufacture of exactly identical profiles and exact point symmetry.In addition thereto, it happens quite often that minor changes indimension are purposefully made on specific locations of the groundcovering element, e.g. for taking into account e.g. a slanted corner ora retraction of a circumferential portion in order to create free spacefor a laying gap, so that the term “substantially” makes sense underthis aspect. Finally, it may be reasonable to make e.g. the projectionsslightly narrower (as measured in the direction of extension of thebasic element side) than the recesses, which are complementary inengagement, in order to thus provide a laying gap between adjacentlylaid ground covering elements. Quite analogous aspects are applicable asregards the use of the term “substantially” in the following descriptionand in the entirety of the claims.

One could also say, in other words, that the profiles at thecircumferential basic element sides of the ground covering element aredesigned such that a particular profile considered may be placedadjacent a substantially identical profile after rotation by 180° so asto provide complementary inter-engagement.

The claims as well as the description of the present patentspecification, at numerous locations thereof, make statements ongeometric relationships, e.g. “square basic element”, “angular groundcovering element”, “projection”, “recess”, “profile”, “wide”,“trapezoidal”. All of these statements relate to a representation of theground covering element in a plan view, i.e. a view from above onto theuseful or upper side of the respective ground covering element, as ifthe same were laid on a base, unless otherwise expressly stated at theparticular location. The ground covering element according to theinvention preferably is a ground covering element provided to makeground coverings for “outdoor use” or for laying areas in the outside. Aparticularly preferred field of use of the ground covering elementaccording to the invention is for traffic areas, in particular suchareas outdoors, e.g. areas for motor vehicle traffic, areas for bicycletraffic, areas for pedestrian traffic. Particularly typical andpreferred are squares, yards, drives, paths, roads, pedestrian areas,loading areas, terraces, parking areas for vehicles, filling stations,commercial traffic areas, industrial traffic areas, factory yards,container sites.

Preferably, the projections and recesses are trapezoidal, which can bemanufactured easily and is favorable for the shear strength of theprojections. As an alternative it is preferred that the projections andrecesses are confined each by a line rounded at least in part, e.g.semi-circular with rounded transition to the left and to the right. Itis to be noted generally that the geometric design of the projectionsand recesses offers a large variety of possibilities.

Preferably, the middle projection and the middle recess each areconsiderably wider than the other projections and recesses,respectively. In this regard, at least 1.5 times as wide is particularlypreferred, at least 1.8 times as wide is still further preferred, and atleast 2.0 times as wide is even further preferred. It will becomeclearer by more detailed statements further below why this difference indimensions will result in a still further improved compromise in thesense of the solution of the object.

Preferably, the ground covering element is provided with spacerprojections on its circumference, with these spacer projections beingleft disregarded in the consideration of the geometric relationshipsdiscussed in the claims. However, it is pointed out that there are alsodesigns in which the geometric relationships mentioned in the claims aremaintained despite the spacer projections. Due to the spacerprojections, ground covering elements are obtained that can be laid inparticularly expedient manner with the laying gap width remaining thesame (as measured transversely of the general direction of extension ofthe circumferential basic element side).

According to a second aspect, the invention relates to a ground coveringelement of artificial stone material, having a basic shape correspondingto a unification of several square basic elements, in particular anangular ground covering element, the ground covering element comprisingprojections and recesses all around the circumference and comprisingretractions on the circumference which result in efficient water passageopenings in a group of the adjacently laid ground covering elements,

-   -   characterized in that the projections and recesses in their        entirety are defined by one profile each for each        circumferential basic element side, there being provided    -   (a) on zero to all circumferential basic element sides,        substantially a first profile each, having—as seen from the        center of the particular basic element upper side—a first end        neighboring projection, a second end neighboring projection and        an end distance projection there-between;    -   (b) on zero to part of the circumferential basic element sides,        substantially a second profile each, having—as seen from the of        the particular basic element upper side—a first end neighboring        projection and a second end neighboring projection;    -   (c) and on zero to part of the circumferential basic element        sides, substantially a third profile each, having—as seen from        the center of the particular basic element upper side—an end        distance projection and an end neighboring projection;    -   (d) wherein, for laying a group of the ground covering elements        adjacent each other,    -   a first profile, if provided, can be applied to a first profile,        if provided, of a neighboring ground covering element; or can be        applied to a second profile, if provided, of a neighboring        ground covering element; or can be applied to a third profile,        if provided, of a neighboring ground covering element;    -   a second profile, if provided, can be applied to a second        profile, if provided, of a neighboring ground covering element;        or can be applied to a third profile, if provided, of a        neighboring ground covering element,    -   and a third profile, if provided, can be applied to a third        profile, if provided, of a neighboring ground covering element.

Ground covering elements of this type according to the invention, in thestate laid adjacent each other, thus lead to ground coverings in whichefficient water passage openings are present in a very considerable partof the ground covering element circumferences. However, due to this, theground covering elements mostly lose the feature “the profile issubstantially point-symmetric with respect to its halving point”.

All statements made so far in the description, of course with theexception of statements that are contradictory to the second aspect ofthe invention, apply analogously also for ground covering elementsaccording to the second aspect of the invention, inclusive of thepreferred developments thereof.

It is emphasized that the terms “first end neighboring projection” and“second end neighboring projection” do not mean that the projectionconcerned begins immediately at an end of the respective circumferentialbasic element side. There may be a distance provided. Rather, what is tobe expressed is that the respective projection is positioned not veryfar from the respective end and in particular that there is noadditional projection present between the end neighboring projection andthe end proper. The first end does not necessarily have to be theleft-hand end of a particular profile, but may optionally be theleft-hand end or the right-hand end of the particular profile.

As in case of the ground covering element according to the first aspectof the invention, the projections and recesses preferably aretrapezoidal, and as an alternative are preferably confined by a linethat is rounded at least in part. The statements made further above areapplicable here as well.

Preferably, the retractions are trapezoidal, as an alternativepreferably confined at least in part by a rounded line. The statementsmade hereinbefore in connection with the shape of the projections andrecesses apply analogously for the retractions as well.

The embodiments described herein provide further details of the first,second and third profiles.

With respect to the first profile and/or the second profile and/or thethird profile, the retraction in each thereof is preferably at least 33%of the width of the respective circumferential basic element side, morepreferably at least 40% of the width, still more preferably at least 50%of the width. In the second profile, it is easier to obtain a maximumpossible width of the retraction than in case of the first and thirdprofiles.

Preferably, the particular retraction at least in part is retracted ortaken back further towards the interior of the ground covering elementthan the recesses or recesses of the particular basic element side. Thewider the respective retraction and the “deeper” the retraction is takenback, the higher the percentage of the sum of the cross-sectional areasof the water penetration passages in relation to the size of thecovering in total.

The present disclosure further defines preferred combinations of firstprofiles, second profiles and third profiles on the circumference of theground covering element. More detailed information in this regard willbe given by the embodiments further below.

As regards the ground covering element according to the first aspect ofthe invention, it is indeed preferred that the first projection, thefirst recess, the third projection and the third recess all havesubstantially the same width (as measured in the direction of thecircumferential basic element side). However, it is possible as well toprovide just the first projection and the third recess withsubstantially the same width and to provide just the first recess andthe third projection with substantially the same width (which, however,is narrower or wider than the width of the afore-mentioned “pair”).

As with the ground covering element according to the first aspect of theinvention, the ground covering element according to the second aspect ofthe invention preferably may have spacer projections and/or at least onedummy gap.

According to a third aspect, the invention relates to a set of groundcovering elements, containing a ground covering element according to thefirst aspect of the invention (first ground covering element) and aground covering element according to the second aspect of the invention(second ground covering element) wherein, for laying a first groundcovering element and a second ground covering element adjacent eachother, the basic side profile of the first ground covering element canbe laid adjacent a first profile or a second profile or a third profileof an adjacent second ground covering element.

The invention thus provides a set of ground covering elements, in whichfirst ground covering elements and second ground covering elements canbe laid adjacent each other in an arbitrary mutual orientation. Thisproperty comes to bear in particularly advantageous manner either at theboundary between a first part of a covering laid with first groundcovering elements and a second part of the covering laid with secondground covering elements or—which is possible without any problem—in acovering with a regular alternation between a first ground coveringelement and a second ground covering element.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention and preferred developments of the invention will bedescribed in more detail hereinafter by way of embodiments shown in thedrawings in which

FIG. 1 shows an angular ground covering element;

FIG. 2 a to 2 d each show the abutment portion of two adjacent groundcovering elements in a fragmentary view;

FIG. 3 shows a second embodiment of a ground covering element that ismodified over that of FIG. 1, with partial regions being broken away;

FIG. 4 shows a portion of a circumference of a ground covering element;

FIG. 5 shows a portion of a circumference of a ground covering element;

FIG. 6 shows a portion of a circumference of a ground covering element;

FIG. 7 shows an angular ground covering element according to a thirdembodiment;

FIG. 8 shows a fourth embodiment of a ground covering element that ismodified over that of FIG. 7, with partial regions being broken away;

FIG. 9 shows an angular ground covering elements according to a fifthembodiment;

FIG. 10 shows a sixth embodiment of a ground covering element that ismodified over that of FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

All of the drawing figures are plan views.

FIG. 1 shows an angular ground covering element 2. In the following, theterm “covering element” will be used throughout in the following insteadof “ground covering element” for reasons of brevity. All coveringelements shown preferably consist of concrete.

The configuration of the covering element 2 is conceivable easiest ifone first speaks of a “basic shape”. In case of the covering element 2of FIG. 1, this basic shape is constituted by the unification of threesquare basic elements 4, 6, 8. The junction lines 10 of the three basicelements 4, 6, 8 are illustrated in broken lines 10. Basic element 4thus has three circumferential basic element sides 12, basic element 6has two circumferential basic element sides 12, and basic element 8 hasthree circumferential basic element sides 12. In basic element 8, thethree circumferential basic element sides 12 are illustrated in brokenlines. When looking at the combination of these three circumferentialbasic element sides and the junction line 10 belonging to basic element8, the basic element square will become apparent immediately.

Basic element 8 shall be considered in more detail in the following:

On each of the three circumferential basic element sides 12, there isprovided a profile 14 composed of projections 16 and recesses 18. Therespective circumferential basic element side 12 at the same timerepresents a neutral line with respect to which the projections 16 areprojecting outwardly and with respect to which the recesses 18 arereceding inwardly.

To begin with, the in FIG. 1 upper, in total horizontally extendingprofile 14 of basic element 8 shall be considered. Starting from theleft-hand end of the basis element side 12 considered, the profile 14begins with a projection 16 a, followed by a recess 18 a, then aprojection 16 b, thereafter a recess 18 b, then a projection 16 c andthereafter a recess 18 c extending up to the right-hand end of basicelement side 12. All projections 16 a to c and all recesses 18 a to care of trapezoidal shape, i.e. they begin with a slightly wider base onthe straight basic element side 12 and taper towards the free end andtowards the base, respectively. The projections 16 and recesses 18follow each other without a gap. The projections 16 a and 16 c closer tothe ends of basic element side 12 (in other embodiments describedhereinafter, reference will be made to “end neighboring projection”) andthe recesses 18 a and 18 c closer to the ends of basic element side 12all have substantially the same mutual width (measured on the basicelement side 12=neutral line). The projection 16 b remoter from the endsof basic element side 12 as well as the recess 18 b remoter from theends of basic element side 12 have the same mutual width and each areabout twice as wide as any of the projections 16 a and 16 c and any ofthe recesses 18 a and 18 c, respectively. The terms “substantially” and“about” have been used purposefully, since—for reasons to be elucidatedin more detail further below—the measurement relationships mentioned arenot to be understood as being exactly so. For example, projection 16 aindeed is somewhat wider than projection 16 c. On the other hand, recess18 c indeed is somewhat wider than recess 18 a; moreover, the corner ofcovering element 2 is slanted with a small taper at the right-hand endof recess 18 c. Finally, it is pointed out that in case of concreteproducts, like the covering element 2 illustrated, indications ofmeasurements and measurement relationships are not to be understood asbeing exact anyway due to the tolerances of the manufacturing mold anddue to the material providing no particularly smooth areas. Aparticularly relevant aspect resulting in a variation in width amongprojections 16 and recesses 18 is the fact that on the circumferentialsides of covering element 2, where a neighboring covering element isadjoining when several covering elements 2 are laid adjacent each other,a laying gap e.g. of a width of 3 to 5 mm is maintained, whereas thereis no laying gap on junction line 10. To provide for certaincompensation in this respect, the more or less mathematical initialdesign of the profile 14 with respect to the width of the projections 16and the recesses 18 and with respect to the positioning of theprojections 16 and recesses 18 is slightly modified.

The profile 14 in consideration is substantially point-symmetric withrespect to its halving point 20, i.e. when the left-hand profile half isrotated by 180° in the drawing plane of FIG. 1, it is identical with theright-hand profile half. The term “substantially” was inserted for thereasons analogous to those set forth hereinbefore.

It is emphasized that the profile 14 described could also be formed“inversely”, i.e. folded by 180° about a halving line located in thedrawing plane, i.e. left-hand end and right-hand end are interchanged.Profile 14 then would begin with a first recess on the left-hand side.

The afore-mentioned widths of the projections 16 and recesses 18 aremeasured on the neutral line 12. This is as a rule the most appropriateplace of the covering element 2 according to the invention.

It is pointed out that the trapezoidal shape of the projections 16 andrecesses 18 constitutes just one of numerous embodiments possible.Instead of this, one could choose e.g. a rectangular shape (whichhowever is more difficult to produce) or a farther projecting or fartherreceding shape e.g. in the form of a low triangle. The profile 14, asseen from the center 22 of the particular basic element, is the same oneach of the three circumferential basic element sides 12, i.e. when theupper profile 14 considered first is rotated clockwise by 90° about thecenter 22, it merges substantially with the in FIG. 1 right-hand profile14 extending in its entirety in vertical direction, and when the upperprofile 14 is rotated by 180° about the center 22, it mergessubstantially with the in FIG. 1 lower profile 14 of the particularbasic element 8, extending in its entirety in horizontal direction. Asregards the use of the term “substantially”, it is referred to thestatements made hereinbefore. Due to the afore-mentioned point symmetryof each profile 14 with regard to the halving point 20, the lowerprofile 14 is substantially a parallel shift of the upper profile 14.

All statements made hereinbefore with respect to the profiles 14 applyanalogously to the basic elements 4 and 6, with the basic element 6 ofcourse having only two circumferential basic element sides and thus onlytwo profiles 14 extending so to speak perpendicularly with respect toeach other.

The geometry of the profiles 14 described allows adjacent coveringelements to be placed adjacent the covering element 2 illustrated inFIG. 1, either in the same orientation or in an orientation rotated by90° (clockwise or anticlockwise) or an orientation rotated by 180°. Theprofiles 14 of adjacent covering elements 2 always fit together incomplementary manner (with some “air” there-between); there is mutualengagement or anchoring of the adjacent covering elements 2 in additionto the mutual anchoring of adjacent covering elements in the laid statethat is obtained by the angular configuration of the covering element 2illustrated.

It is pointed out that covering elements 2 according to the inventionindeed are supposed to have a basic shape corresponding to a unificationof several square basic elements, but that the number of the basicelements and the orientation of the unification can be chosen. Forexample, it would be possible to unify e.g. three basic elements 4, 6, 8(or also two basic elements or four basic elements) in a straightseries, or to provide an L-shaped covering element 2 by addition of afurther basic element on the right-hand side of basic element 8, or toprovide a T-shaped covering element 2 by addition of a further basicelement to the upper side of the middle basic element 6, or to provide acruciform covering element 2 by addition of a further basic element tothe upper side of the middle basic element 6 and addition of a furtherbasic element to the left-hand side of the middle basic element 6, etc.

It is expressly emphasized that the invention, as an alternative, alsoprovides a ground covering element whose basic shape consists of onesquare basic element only, but otherwise has the cogent featuresdescribed in the present patent specification and optionally furtherpreferred features.

It is illustrated by way of FIGS. 2 a to d why the number of “threeprojections” and “three recesses” according to the invention providesfor especially good results. Each of the partial figures a to dschematically illustrates a profile 14 of a circumferential basicelement side 12. In FIG. 2 a, the basic element side is divided intoeight projections 16 and eight recesses 18 which all have the samemutual width. In partial FIG. 2 b, the basic element side is dividedinto three projections 16 and three recesses 18 which all have the samemutual width. In partial FIG. 2 c, the basic element side is dividedinto two projections 16 and two recesses 18 which all have the samemutual width. The alternative with just one projection and one recess isnot illustrated as it results in incomplete inter-engagement between twocovering elements.

Each of the basic element sides 12 of the two adjacent covering elements2 a and 2 b do not extend parallel to each other (as desired for perfectlaying), but extend at an angle 24 with respect to each other, withangle 24 being the same in all partial FIGS. 2 a to d.

If two adjacent covering elements 2 a and 2 b are arranged beside eachother with a misalignment in the sense of the angle 24 mentioned, whichmay occur due to inaccurate laying work or by displacement of individualcovering elements 2 by traffic loads in the laid state, FIG. 2 a stillmaintains a residual inter-engagement by the last projection 16 at theright-hand end of basic element side 12 of the one covering element 2 aand a recess 18 at the corresponding end of the basic element side 12 ofthe other covering element 2 b. In case of the covering elements 2 a and2 b of FIG. 2 b, the left hand trapezoidal side of the rightmostprojection 16 c of covering element 2 a and the left-hand trapezoidalside of the rightmost recess 18 c of covering element 2 b have migrateda certain distance to the left, but in this situation there is just lefta residual inter-engagement between this projection 16 c and this recess18 c (although with lesser depth of positive engagement). In case of thecovering elements 2 a and 2 b according to FIG. 2 c, there is noresidual inter-engagement left in this situation. The conclusion to bedrawn therefrom is that the residual inter-engagement effect in case ofangular misalignment between adjacent covering elements is the betterthe larger the number of projections and recesses over a given length ofa basic element side.

A further aspect is the strength or load-bearing capacity of theinter-engagement between two adjacently laid covering elements 2 a and 2b in the correctly laid state, i.e. with mutually parallel basic elementsides 12 with so little spacing from each other as corresponds to theusual laying gap. In this respect, the shear strength, i.e. the coveringelements 2 a and 2 b have forces of opposite directions applied theretoin the direction parallel to the basic element sides 12, decreases withincreasing number of projections 16 and recesses 18 on a given length ofthe basic element side 12. On the one hand, the overall shear areasummed up from the individual projections 16 becomes ever smaller withincreasing number of projections (since the laying gap sections betweenthe oblique trapezoidal sides do not contribute in the overall sheararea and since a loss in overall shear area is caused in that, on alarger number of projections, the cross-sectional area of shear is notlocated in the root of the projection, but in the projection portionthat is tapered in comparison therewith). On the other hand, there isthe effect that, with a larger number of projections, it is by far notthe entire number of projections that provides a supporting effectagainst shearing, but less than half thereof in accordance withexperience. The aspect of shear strength thus speaks for making thenumber of projections and recesses as small as possible for a givenlength of the basic element side.

On consideration of these aspects, the inventors thus have arrived atthe conclusion that the number of three projections and three recessesrepresents the optimum compromise between residual inter-engagementeffect in case of angular misalignment and high shear strength.

This compromise is still further enhanced when the pairs of projection16 a and recess 18 a and projection 16 c and recess 18 c closer to therespective ends of the basic element side are of lesser width than thepair of projection 16 b and recess 18 b arranged there-between, cf. FIG.2 d.

The embodiment of a covering element 2 according to FIG. 3 differs fromthe embodiment according to FIG. 1 in that straight dummy gaps 26 extendat those locations where the junction lines 10 were illustrated inFIG. 1. Dummy gaps are gaps extending from the upper side downwardlyinto covering element 2 up to a specific depth of e.g. 5 mm only. Thedummy gaps 26 provide for an optical subdivision of covering element 2into three partial covering elements which, apart from the profiles 14,correspond to the three basic elements 4, 6, 8. As measured transverselyof their direction of extension, the dummy gaps 26 have a widthcorresponding substantially to the height of the projections 16, asmeasured from the bottom of the recesses 18 and, in addition, theafore-mentioned laying gap width (the latter being measured transverselyto the general direction of extension of profile 14). It is possible notonly with the embodiment according to FIG. 3, but with all embodimentsthat the upper sides of the projections 16 are slightly lowered withrespect to the remaining upper side of covering element 2, e.g. by 4 to8 mm. The consequence hereof is that the inter-engagement between twoadjacent profiles 14 is optically less apparent in the laid covering ofseveral covering elements 2. The dummy gaps 26 so to speak represent anoptical continuation of the groove formed by the two adjacent profiles14 and the laying gap there-between.

Moreover, FIG. 3 illustrates the possibility of providing spacerprojections 28 distributed over the circumference of the coveringelement 2. In the illustrated embodiment, the spacer projections 28 areof semi-circular cross-section each and are provided on the—as seen fromthe center 22 of the respective basic element upper side—leftmostprojection 16 of the corresponding profile 14 each. In FIG. 3, the sizeof the spacer projections 28 is shown in enlarged form as compared totheir natural size in order to make the spacer projections clearlyvisible at all. The spacer projections 28 facilitate laying of thecovering elements 2, since the adjacent covering element 2 to be laidnext can be placed simply in physical contact between the spacerprojections 28 of the already laid covering element 2 and the spacerprojections 28 of the new covering element 2 to be laid. In this manner,a laying gap of uniform width is created. It is emphasized that thespacer projections may be selectively of other cross-sectional geometryand be located on other locations than those shown in FIG. 3. It ispreferred that the spacer projections begin only a certain distancebelow the covering element upper side and extend from there to the verybottom side of the covering element 2. The spacer projections 28 areformed integrally with the remainder of the covering element 2 ofconcrete.

FIG. 3 finally illustrates the possibility of confining the projections16 and the recesses 18 by a rounded line each (rounded throughout orrounded in portions and straight in portions).

It is emphasized furthermore that the features “dummy gaps 26” and“spacer projections 28” need not necessarily be realized in combination,but that it is possible to provide covering elements 2 with at least onedummy gap 26 and/or with spacer projections 28. It is possible toprovide just one dummy gap 26 or more than two dummy gaps 26, e.g. tooptically subdivide the unification of the basic elements 6 and 8 intothree parts by means of two dummy gaps 26. It is possible, furthermore,to provide one or more non-linear dummy gaps, extending e.g. inconformity with the path of profile 14.

FIGS. 4 to 6 illustrate profiles 14 a, 14 b, 14 c that are modified withrespect to profile 14 of FIG. 1. Here too, the neutral line 12 is shownin each of the figures. The distance from the respective left-hand endto the respective right-hand end corresponds to that of a basic elementside in FIG. 1.

The profile illustrated in FIG. 4 is a profile of the type referred toas “first profile 14 a” in the present text. In comparison with theprofile 14 of FIG. 1 (e.g., considering the “horizontal” profile 14 tothe upper right in FIG. 1), the second projection 16 b is renderednarrower to such an extent that it has a width (as measured in thedirection of the neutral line 12) corresponding to the width of thirdprojection 16 c. Between the thus formed second projection 16 b and thethird projection 16 c, there is located a retraction 30. Retraction 30is further retracted towards the interior of covering element 2 than thebottom of recess 18 a and the bottom of recess 18 c. Retraction 30 intotal is of trapezoidal shape. In the introductory part of thespecification, first projection 16 a is designated “first endneighboring projection” (as it is located in the neighborhood of thefirst end of the profile), second projection 16 b is designated “enddistance projection” (as, in comparison with the other projections, itis arranged at a larger distance from the ends of the profile), andthird projection 16 c is designated “second end neighboring projection”(as it is located in the neighborhood of another end of the profile).

The profile illustrated in FIG. 5 is a profile of the type referred toas “second profile 14 b” in the present text. In comparison with theprofile 14 of FIG. 1 (e.g. considering the “horizontal” profile 14 tothe upper right in FIG. 1), the second projection is omitted completelyso that of the projections only the first end neighboring projection 16a and the second end neighboring projection 16 c are left. Between theseprojections 16 a and 16 b, there is located a retraction 30 (which thusreplaces first recess 18 a, second projection 16 b and second recess 18b) which, as in case of FIG. 4, is retracted further towards theinterior of covering element 2 than the bottom of recess 18 c.

The profile illustrated in FIG. 6 is a profile of the type referred toas “third profile 14 c” in the present text. In comparison with theprofile 14 of FIG. 1 (e.g. considering the “horizontal” profile 14 tothe upper right in FIG. 1), the first projection 16 is omitted andsubstituted by a corresponding broadening of the first recess 18 a. Thesecond projection 16 b of FIG. 1 is rendered narrower to the same extentas in case of profile 14 a in FIG. 4. The retraction 30 in FIG. 5 alsocorresponds to the retraction 30 in FIG. 4. In the description,projection 16 b is designated “end distance projection” (since, in thelight of the just outlined history of origin, it corresponds to the enddistance projection 16 b in FIG. 4 and although there is no furtherprojection between it and the left-hand end of the profile 14 c). It isemphasized that the profiles 14 a, 14 b, 14 c as an alternative may alsobe designed such that they are folded by 180° about their halving axislocated in the drawing plane, so that they would each begin with recess18 c at the left-hand end.

In the first profile 14 a of FIG. 4, the projections 16 a, 16 b, 16 call have substantially the same width (as measured in the direction ofthe neutral line 12); the recesses 18 a and 18 c also have substantiallythe same mutual width and substantially the same width as theprojections (as measured in the direction of neutral line 12). Asregards the reasons for using the term “substantially”, these havealready been pointed out hereinbefore in connection with FIG. 1. Inparticular, one can see in FIG. 4 that the first end neighboringprojection 16 a in reality is somewhat wider than the projections 16 band 16 c. It is expressly pointed out that the end distance projection16 b could very well be wider towards the right than is illustrated,without this interfering with the inter-engagement with a neighboringcovering element 2 to be discussed in more detail further below.

As regards the second profile 14 b of FIG. 5, the two projections 16 aand 16 c and the recess 18 c all have substantially the same width.

In the third profile 14 c of FIG. 6, the projections 16 b and 16 c andthe recess 18 c are substantially of the same width; the recess 18 a issubstantially twice as wide as in FIG. 1. Here, too, the end distanceprojection 16 b indeed could be wider towards the right without thisinterfering with the inter-engagement.

A comparison of FIGS. 4, 5, 6 directly reveals that the first profile 14a (of course upon rotation thereof by 180°) could be laid selectivelyadjacent an additional first profile 14 a or a second profile 14 b or athird profile 14 c. The second profile 14 b, too, can be laidselectively adjacent a first profile 14 a, a second profile 14 b and athird profile 14 c. The third profile 14 c also is adapted to beselectively laid adjacent a first profile 14 a or a second profile 14 bor a third profile 14 c. This becomes clear also from the history oforigin of profiles 14 a, 14 b, 14 c since, as compared to the profile 14of FIG. 1, projections have been cut off completely or in part, whilehowever no essential changes have been made, with the exception of theretractions 30. It is recognizable furthermore that, with respect to theretractions 30 (in so far as they are not reduced in a small part byprojections 16 of the neighboring covering element 2 engaging therein),there are left elongate openings in the covering of a plurality ofadjacently laid covering elements 2. These openings represent efficientwater passage openings through which water precipitated may flow offinto the bed underneath the covering, so that it need not be dischargedinto a discharge channel system. The depth of the retractions 30 withrespect to the neutral line 12 determine—in addition to the width of theretractions 30, though this cannot be chosen very freely—the percentageof the water passage openings in the total covering. The purpose of thedescribed change from the profile 14 of FIG. 1 to the profiles of FIGS.4 to 6 consisted in providing covering elements 2 which in the laidstate form water penetration passages in the covering.

If a second profile 14 b is laid in inter-engagement with a secondprofile 14 b, an inter-engagement is established that provides forpositive locking in just one of two possible directions. The same holdsif a third profile 14 c is laid in inter-engagement with a third profile14 c. However, if a first profile 14 a is laid in inter-engagement witha first profile 14 a, positive locking in the two directions possible isachieved (since projection 16 c engages in recess 18 a framed on bothsides by projections). The same holds for inter-engagement between afirst profile 14 a and a second profile 14 b as well as forinter-engagement between a first profile 14 a and a third profile 14 c.Also with inter-engagement of a second profile 14 b and a third profile14 d, there is a positive locking effect achieved in the two directionspossible, i.e. towards the left and towards the right in FIGS. 4, 5, 6.The result of this is that covering elements 2 having only secondprofiles 14 b all around their circumference and covering elements 2having only third profiles 14 c all around their circumference are notparticularly advantageous under the aspect of inter-engagement on eachcircumferential basic element side. However, this aspect is not ofextremely large significance especially with angular covering elements 2as shown in FIG. 1, since the overall configuration of the coveringelement 2 already results in effective mutual anchoring of the coveringelements 2 in the covering.

Good inter-engagement and/or good anchoring due to the covering elementconfiguration is advantageous not only for the laid state but also forholding together of covering elements manufactured together on a plateof the manufacturing machine, when these are machine-laid using agripper.

It has already been pointed out hereinbefore that it is basicallypossible to make covering elements 2 for providing coverings withefficient water passage openings which, at the circumference thereof,have either only first profiles 14 a or only second profiles 14 b(better, however, with at least one exception) or only third profiles 14c (better, however, with at least one exception) or an arbitrarycombination of profiles 14 a, 14 b, 14 c.

FIG. 7 illustrates an embodiment of a water passage opening coveringelement 2 which has no first profile 14 a, but five second profiles 14 band three third profiles 14 c. As regards the locations of such secondprofiles 14 b and such third profiles 14 c, it is expressly referred toFIG. 7.

FIG. 8 illustrates schematically (i.e. without explicit indication ofthe profiles) a modification in which four second profiles 14 b and fourthird profiles 14 c are provided, with these being distributed moreoverin different manner along the circumferential basic element sides 12. Asregards the distribution thereof over the circumferential basic elementsides 12, it is expressly referred to FIG. 8.

FIG. 9 shows an embodiment having two first profiles 14 a, five secondprofiles 14 b and a third profile 14 c. As regards the individualcircumferential basic element sides with the individual profiles, it isexpressly referred to FIG. 9. The transition from the embodiment of FIG.7 to the embodiment of FIG. 9 is conceivable such that two thirdprofiles 14 c have been replaced by two first profiles 14 a.

Analogous with FIG. 3, FIG. 10 shows an embodiment in which theadditional features “dummy gaps 26”, “spacer projections 26” and“rounded projections 16” or “rounded recesses 18” or “rounded retraction30”, respectively, can be seen. Here too, the detailed statements madehereinbefore in relation to FIG. 3 hold in particular with respect tothe non-existing cogent requirement of providing several of thesefeatures in combination.

1. An angular ground covering element (2) of artificial stone material,corresponding to a unification of several square basic elements (4; 6;8), the ground covering element (2) comprising projections and recessesaround its circumference and retractions (30) on the circumference fordrainage of water, characterized in that the projections and recesses oneach circumferential basic element side (12) are defined by a profile,extending from a first end to a second end of the basic element side,said profile being chosen from the group of profiles consisting of: (a)a first profile (14 a) having a first end neighboring projection (16 a)adjacent the first end of the basic element side, a second endneighboring projection (16 c) adjacent the second end of the basicelement side and a third projection (16 b) there-between, said thirdprojection being spaced from the ends, wherein said retraction (30) ispositioned between said second projection and one of said first andthird projections; (b) a second profile (14 b) having a first endneighboring projection (16 a) adjacent the first end of the basicelement side and a second end neighboring projection (16 c) adjacent thesecond end of the basic element side, wherein said retraction (30) ispositioned between said first and second projections; and (c) a thirdprofile (14 c) having a first projection (16 b) spaced from said firstand second ends and a second end neighboring projection (16 c) adjacentthe second end of the basic element side, wherein said retraction (30)is positioned between said first and second projections.
 2. The groundcovering element according to claim 1, characterized in that saidprojections and recesses have a trapezoidal profile.
 3. The groundcovering element according to claim 1, characterized in that saidprojections and recesses are confined by an at least partly roundedline.
 4. The ground covering element (2) according to claim 1,characterized in that said retractions (30) have a trapezoidal profile.5. The ground covering element (2) according to claim 1, characterizedin that the retractions (30) are each confined by an at least partlyrounded line.
 6. The ground covering element according to claim 1,characterized in that, with respect to the first profile (14 a), thefirst end neighboring projection (16 a) begins substantially at thefirst end of the basic element side (12), a first recess (18 c) isprovided adjacent to the second end neighboring projection (16 c), saidfirst recess extending up to the second end of the basic element side(12), a second recess (18 a) is provided between the third projection(16 b) and one of the first and second end neighboring projections (16a; 16 c); and wherein said first and second end neighboring projections(16 a, 16 c) and said first and second recesses (18 a, 18 c) havesubstantially the same width.
 7. The ground covering element accordingto claim 1, characterized in that, with respect to the second profile(14 b), the first end neighboring projection (16 a) begins substantiallyat the first end of the basic element side (12), a recess (18 c) isprovided adjacent to the second end neighboring projection (16 c), saidrecess extending up to the second end of the basic element side (12);and wherein said first and second projections (16 a, 16 c) and saidrecess (18 c) have substantially the same width.
 8. The ground coveringelement according to claim 1, characterized in that, with respect to thethird profile (14 c), a first recess (18 c) is provided adjacent to thesecond end neighboring projection (16 c) said first recess extending upto the second end of the basic element side (12), a second recess (18 a)is provided adjacent to the first projection (16 b) said second recessextending up to the first end of the basic element side (12); andwherein said second end neighboring projection (16 c) and said firstrecess (18 c) have substantially the same width and said second recess(18 a) has substantially twice the width with respect thereto.
 9. Theground covering element according to claim 1, characterized in that theretraction (30) is at least 33% of the width of the circumferentialbasic element side (12).
 10. The ground covering element according toclaim 1, characterized in that the retraction (30) extends further intothe ground covering element than the recesses of the basic element side(12).
 11. The ground covering element according to claim 1, furtherincluding spacer projections (28) on its circumference.
 12. The groundcovering element according to claim 1, further including at least onedummy gap (26) on its upper side, which generally extends along thejunction line of the unification of two adjacent basic elements.